Localities, hamlets and towns
|Discovery Bay||Discovery Bay||Nelson, Wade Junction, Kentbruck, Mount Richmond, Tarragal||The land behind the shore of Discovery Bay, from the South Australian border to the Bridgewater Lakes at Tarragal, has a series of transgressive dunes mantling stranded barrier coastlines. The transgressive dunes consist of a succession of unconsolidated Holocene dunes overlaying Pleistocene calcarenite dunes on the latter’s seaward side. Holocene dunes may have been remobilised after defoliation by fire and agriculture. Where sand has blown up over the scarp of the Bridgewater fault, west of Kentbruck, dunes overly basalts on the Normanby Platform. |
The Pleistocene calcarenite dunes are truncated. Some of the swamps may have been created by deflation down to base level set by the water table or the surface of the calcarenite. It is unknown if these surfaces, under the Holocene dunes, were sufficiently low in elevation for the Holocene sea to penetrate the fore-dunes and invade land behind the modern coast. But analysis of LiDAR data suggests this did not occur.
This system is incised by the Glenelg River and Johnstone Creek such that the sea can flow into adjacent low land behind the modern coast via the estuary of the Glenelg River.
|Prospective in the low lying areas influenced by the estuary of the Glenelg River and by over-wash, particularly into Johnstone Creek. The extent to which wind-blown sand has buried CASS is unclear.|
Swales and swamps not directly influenced by the sea, may have received sufficient cyclic salt to develop inland ASS. However, formation of metal sulfides may be limited by the iron content of the sediments in these features.
|Glenelg River estuary and Long Swamp||Nelson, Wade Junction||The Glenelg River has incised a deep gorge through the coast which has been backfilled since the Pleistocene. It’s estuary has a swamp to the west (Holloway Swamp) and a lagoon (Mud Lagoon) to the east which is connected to Long Swamp by Eel Creek. Long Swamp extends east to Lake Mombeong and occupies the low land between the Holocene coast and the transgressive dunes and stranded barriers.|
It is unclear if the Glenelg River penetrated the coastline at locations other than its current outlet, during the Holocene. Boutakoff (1963) suggested that it flowed through Mud Lagoon to an entrance now occupied by Holocene deposits. A mid-Holocene bench can be found at the end of Black Swan Road and below the car park at the end of Beach Road along the shore of the modern estuary, suggesting that the current outlet was open at the mid-Holocene high sea stand.
|Prospective in the dune-fields, flood plains, swamps, lagoons and lakes from the South Australian border to Lake Mombeong. It is unclear to what extent modern wind-blown dunes overlay CASS. Analysis of LiDAR data suggests thte the influcence of the sea doesn’t extend past Long Swamp, i.e. Noble Rocks.|
|Glenelg River upstream of the estuary||Nelson, Wanwin, Drik Drik, Dartmoor||The Glenelg River has incised a deep gorge into the limestone (Bridgewater formation). The river has numerous small alluvial plains along its course within the gorge. Locals suggest that the modern tidal influence extends many kilometres up the river from Nelson to at least Dartmoor where there is a rock cascade.||Analysis of aerial photography, shows numerous small alluvial plains under which CASS may occur. The mid-Holocene peak may have reached further upstream than the cascade at Dartmoor, e.g. the 10 m AHD contour is at the same latitude as Red Hill Swamp (10 km North of Dartmoor), but it is considered unlikely.|
|Lake Mombeong, Dead Horse Swamp and The Sheep Wash||Kentbruck||Blowouts have cut Lake Mombeong, Dead Horse Swamp and The Sheep Wash from Long Swamp. Lake Mombeong is an unusual feature as it appears to be supplied by fresh ground water. It could be a dissolution feature.|
Dead Horse Swamp is at a higher elevation than Lake Mombeong.
These swamps and lakes may be too elevated to have been affected by the mid-Holocene sea rise.
|Analysis if LiDAR data suggests that these features are not prospective. However, Lake Mombeong may receive sufficient cyclic salt to contain IASS in its bottom sediments.|
|Malseed Lake, Swan Lake and Johnstone Creek||Swan Lake is formed by the damming of Johnstone Creek by dunes. The mid-Holocene high sea-stand may have entered Johnstone Creek as far as Swan Lake. The outlet of Swan Lake spills over a calcarenite threshold. Neighbouring Malseed Lake has been shown to have marine faunal species indicating they were once open to the sea (Timms, 1977). Malseed Lake may not have been connected to Swan Lake.||Analysis if LiDAR data suggests that Swan Lake is not prospective. Prospective in Johnstone Creek and the surrounding depressions such as Malseed Lake.|
|Bridgewater Lakes||Tarragal||Bridgewater Lakes are cut off from the sea by transgressive dunes. They are fresh water lakes fed by ground water.||Not prospective for CASS although they may receive sufficient cyclic salt to form inland ASS.|
|Portland Peninsula||Bridgewater Bay||Lower Cape Bridgewater||Behind the cliffed coast of Bridgewater Bay, there is a low flat plain. It is not clear if the cliffs are continuous along the shore of Bridgewater Bay since aeolian and littoral sand mantle the cliffs. The sea may have entered this plain during the mid-Holocene sea-stand if there is a gap which is now hidden by sand.||Not prospective for CASS in the low plain, although it may receive sufficient cyclic salt to form inland ASS. However, this depends on permanent waterlogging to preserve the IASS.|
|Wattle Hill Creek, Fawthrop Lagoon||Portland||An estuary with a tidal creek and lagoon surrounded by swamp. Wattle Hill Creek has incised a valley through the eastern cliffs of the Portland Peninsula. Wattle Hill Creek is now extensively modified at its outlet where as it used to flow past a gravelly spit at Battery Hill.||Prospective in the creek, lagoon, swamp and flood plain. Made land may also be prospective since exposures along the west bank of Fawthrop Lagoon reveal estuarine sediments.|
|Portland Bay||Portland Bay from Dutton Way to Crowe Hill||Portland North, Bolwarra, Allestree, Narrawong, Tyrendarra||The land and sea floor of Portland Bay has been submerged and exposed at various times. The inland extent of submergence is marked by a grassy bluff that was once a marine cliff which fades out east of Darlots Creek. The grassy bluff does not sweep around in a continuous curve but turns inland at Allestree and is disjointed at the Surry River and Fitzroy Rivers, where the bluff steps inland at Mount Clay. West of the Surry River, the bluff is fronted by a plain that was once a lagoon at the back of a Pleistocene beach ridge, the latter is welded to the bluff at Allestree and ending at the Surry River next to Mount Clay. This beach ridge is in turn is fronted by a series of parallel beach ridges from the Pleistocene and Holocene. The Pleistocene ridges have become hardened to form calcarenite, some are currently submerged. Swamps (some are now drained) occupy the low land between the dune ridges. Only the outer Pleistocene barrier ridges form continuous curves around Portland Bay.||Prospective in the low land between the bluff west of Allestree, or the first Pleistocene barrier ridge (east of Allestree) and the shore (The Princes Highway is on the second beach ridge between Allestree and Narrawong). The inland extent of prospective land is unclear where there are multiple Holocene ridges. Consultant investigations have proved that CASS is present behind the modern fore-dunes, west of Camp Road.|
|Surry River estuary||Narrawong||Flood prone land around the Surry River between the outlet at Narrawong and Wade Road, may be influenced by the mid-Holocene high sea-stand. Flood prone land includes the swamps occupying the corridors between the Pleistocene barrier ridges.||Prospective in the low land up stream to Wade Road. This is supported by soil sampling in the flood plain (crossed by Williams Road).|
|Fitzroy River estuary||Narrawong, Tyrendarra, Crowes Hill, Tyrendarra East||Fitzroy River and Darlots Creek flow along the edge of the Tyrendarra lava flow to empty into the estuary of the Fitzroy River between the Holocene coastal dunes and Pleistocene calcarenite dunes. Two gaps where the lava flowed through the outer Pleistocene barrier ridge, are filled with Holocene sediments. Currently the outlet of the Fitzroy River is at Thompsons Road, east of the Tyrendarra lava flow. The outlet may have been at several locations along the coast.||The low land along the estuary of the Fitzroy River and upstream along the Fitzroy River and Darlots Creek, and the low land along the narrow corridors between the Pleistocene barrier ridges and the basalt, are prospective. This is supported by soil sampling.|
|Codrington coast between Tyrendarra East and Yambuk||Tyrendarra East, Codrington, Yambuk||A bay with multiple barrier ridges. Holocene barrier dunes merge onto the Pleistocene calcarenite dunes at Eumeralla. The corridor between the Holocene barrier and Pleistocene barrier is now separated into individual basins by blow-outs from the Holocene barrier.||Prospective between the modern outer barrier and the inner calcarenite stranded dunes. This is supported by soil sampling.|
The plain behind the stranded dunes is not prospective as it is to high to have been influenced by the Holocene sea.
|Eumeralla River estuary, Lake Yambuk, Sheepwash Swamp||Yambuk||Eumeralla River has incised channel through the softer surface sediments into the limestone base. This provides a basin for a levee bank system of deposits in the estuary. The channel has been backfilled with more recent sediments. |
The lower parts of the landscape down-stream of Hummocks Road may contain estuarine sediments. It is not clear if the low coastal plains between Carrols Road and Crags Road, e.g. Sheepwash Swamp, were influenced by the mid-Holocene high sea-stand. Drains were installed to connect these former swamps and wetlands to Lake Yambuk and so now may be influenced by estuarine water.
|Prospective downstream of Hummocks Road. Soil sampling in Sheepwash Swamp suggest that acid sulfate soil is present but it is not known if it is IASS or CASS.|
|Cape Rameur||Cape Rameur, The Crags and Aringa||Aringa, Port Fairy||There are low swamps inland of the cliffs west of Port Fairy. The swamps are unlikely to have been influenced by Holocene seas but they may contain peat swamps which receive cyclic salt.||Not prospective for CASS but have the potential to contain IASS.|
|Port Fairy Bay||Port Fairy to Reef Point||Port Fairy, Rosebrook, Crossley||A modern barrier and with a lagoon, Belfast Lough, fed by the Moyne River after it passes through Pleistocene barriers. The land between the modern barrier and the edge of the basalt flow from Mount Napier, has several parallel curved calcareous sand ridges (the Princes Highway is on a Pleistocene barrier). The inner barriers had a lake behind them but the surface is too high for the sea to have penetrated during the mid-Holocene high sea-stand. The Moyne River may be confined within its alluvial plain.||All lowland seaward of the Princes Highway, and at the delta of Moyne River where it enters Belfast Lough, is prospective. This supported by soil sampling.|
|Killarney Beach||Killarney||There is a back swamp (Sheedy Swamp?) behind the Holocene barrier. This system extends east from Killarney Recreational Reserve (behind Sisters Point) to the Tower Hill tuff. The dunes are mounted on basalt which outcrops along Killarney Beach and each side of the outlet of the swamp.||Prospective in the back swamp and dunes.|
|Tower Hill Beach||Tower Hill||A bluff formed from tuff and Holocene dunes. These dunes have blown up on the land behind the bluff, making it difficult to assess the presence of marine and estuarine sediments.||The potential to contain CASS is unclear. Therefore, it has been assumed that the land occupied by the Holocene dunes and the lowland behind the dunes is prospective.|
|Kelly Swamp, Lake Pertobe and Merri River||Illowa, Dennington, Warrnambool||Merri River has incised into limestone and basalt to empty into a broad corridor between an outer barrier and an inner barrier. Its course is trapped in the incision in basalt and is tidal for some distance upstream. Its course in the corridor and its outlet to the sea have varied and includes an incision to the south east through the outer barrier to reach the sea at Pickering Point. The Merri River now empties to the sea via a drain dug through planed-off Pleistocene calcarenite dune ridges, to Lady Bay. |
Lake Pertobe is extensively modified and sits behind a prograding coast line.
The outer barrier consists of Holocene dunes mounted on a Pleistocene dune calcarenites. The north-western end of the calcarenites is hidden under the Holocene deposits while the south-eastern end emerges as rock platforms and cliffs. The inner barrier consists of Pleistocene calcarenites plastered on the front of a Pleistocene bluff.
The corridor, and the Merri River during floods, empty to the sea via Kelly Swamp which in turn empties through an unnamed estuary at the north-western end of a long flat swampy plain. The south-eastern end of corridor has planed-off calcarenite dune ridges within which the Merri has incised a shallow valley that is filled with swamp sediments.
|Prospective in the broad corridor and along the various courses of the Merri River. Land surrounding Lake Pertobe is prospective. Rampant et al., (2003) found CASS at Kelly Swamp.|
|Hopkins River||Warrnambool||The Hopkins River has incised between neighbouring kast and basalt landscapes. There are no Holocene estuarine deposits on land.||Not prospective.|
|Twelve Apostles Coast||Logans Beach and the Hopkins River||Logans Beach, Warrnambool||On the south-eastern side of the mouth of the Hopkins River, a Holocene beach is mounted on Pleistocene calcarenite dunes. This system merges onto the Port Campbell Limestone cliff. There are sand dunes left behind the shoreline as it regressed from mid-Holocene peak. While it is recognised that the sea enters the Hopkins River, it is difficult to identify land downstream of Tooram Rocks, which may have estuarine sediments.||Not prospective since analysis of LiDAR data suggests nearly all of the alluvial plane is above 2 m AHD, but the sediments of the Hopkins River have the potential to contain metal sulfides.|
|Curdies Inlet, Curdies River and A’Becketts Creek||Peterborough, Curdie Vale, Curdies||The lower reach of the Curdies River has cut a valley into limestone and other sediments. Its course is controlled by faulting. Currently it empties into a lagoon fronted by Holocene dunes and a sand bar. But for snags, the lagoon is navigable for many kilometres upstream to the reach between Curdie Vale and Curdies. Estuarine sediments underlay the current flood plain. The flood plain narrows upstream of Curdie Vale, being confined within steepening slopes.||Its flood plains are prospective. This is supported by soil sampling. Despite the river having cut into limestone, sulfidic material and water may not be in contact with limestone and so it can not be assumed that limestone will neutralize sulfuric material or acidic leachates.|
|Two Mile Bay||Port Campbell||A preserved bluff protected behind a rock platform. This unusual feature preserves sediments laid from the higher sea-stand of the mid-Holocene.||Prospective in the low land.|
|Port Campbell||Port Campbell||An incised valley within Port Campbell limestone. The valley occupies a narrow confined space. Fresh to brackish water drains from a tidal creek into a small estuary. The marine influence probably stops at a shelf.||The swamp and the flood plain at the head of the bay through which a tidal creek flows, are prospective.|
|Otway Ranges Coast||Sherbrook River||A river occupying a valley shallowly incised into Port Campbell Limestone with a narrow and confined short lagoon.||Land on each side of the lagoon is prospective.|
|Bellarine Peninsula||Gellibrand River and La Trobe Creek||Princetown, Lower Gellibrand, Burrupa||A confined estuary and tidal river. The Gellibrand River exits to the sea, through a gap between Pleistocene barriers. Upstream from Princetown, the river has high levee banks with back swamps or flood plains. It is tidal for many kilometres upstream, including upstream of the Great Ocean Road bridge at Lower Gellibrand. Upstream of Lower Gellibrand, some sections of the valley narrow to confine the river to a narrow flood plain with high levee banks. It is unclear if these have retarded penetration of estuarine waters during the Holocene.||Prospective land occurs on the flood plains of the Gellibrand River upto and beyond the Great Ocean Road to Burrupa. Where the flood plain extends up the Gellibrand River’s tributaries, i.e. La Trobe Creek, Boggy Creek, Nariel Creek, Bryant Creek and Atkinson Creek, this land is also prospective. Despite being cut into limestone, water may not be in contact with limestone and so it is not assumed that limestone will neutralize sulfuric acid produced from disturbed CASS.|
|Johanna River and Stratford Creek at Johanna||Johanna||A confined estuary sitting in an incised valley between Cretaceous sediments, Tertiary sediments and Holocene dunes mantling Pleistocene calcarenite barrier dunes. Aerial photography suggests the river has incised a narrow valley as it passes through the calcareous sands in the dunes blocking the estuary. Lobes of sand on either side make its flood plain narrow.||Prospective in the low land of the alluvial plain behind the barrier. CASS may be buried by sand along the estuary and under the Holocene dunes behind the beach.|
|Aire River||Hordern Vale and Glenaire||Three rivers, the Aire, Calder and Ford, enter a basin between Cretaceous sedimentary hills and the Pleistocene dune calcarenites. The latter separates the basin from the sea. During the Holocene, the basin has filled with alluvial and estuarine sediments to form a wide plain with a lagoon and an estuary.||Prospectivity proved by Fitzpatrick et al., (2007). Prospective land would not extend up the river gorges.|
|Mounts Bay and Barham River estuary||Merano and Apollo Bay||The estuary of the Barham River is behind a barrier formed from a spit which has extended from Hayley Point to the southern side of Point Bunbury. The Barham River flows over bedrock through a narrow opening between the spit and Bunbury Point. The bedrock is the south facing slope of Bunbury Point. The estuarine and lagoonal Holocene sediments extend as far inland as the terraces that mark the limit of the last inter-glacial high sea stand (the 10 m contour is just inland of these terraces).||Prospective land extends from the modern shore to the Pleistocene terraces and upstream in the Barham River flood plain to the mid-Holocene high sea-stand tidal influence. Consultant’s reports for development along the Barham River and the report by Fitzpatrick et al. (2007) have proved CASS is present, including actual acid sulfate soil.|
|Apollo Bay (Point Bunbury to Wild Dog Creek)||Apollo Bay||Apollo Bay is backed by a moderate slope which descends to the beach with a series of benches.||Not prospective.|
|Parker River and other minor waterways along the east coast of the Otway Ranges||Apollo Bay, Kennet River, Wye River, Lorne||Most creeks and rivers flowing across the eastern coast of the Otway Ranges have stony and/or rock beds where they cross the coast. For example, the Parker River enters the sea over a series of cascades and small falls. This geomorphology does not allow placement of permanently anoxic estuarine, lagoonal or swampy sediments in which metal sulfides can form. The only exceptions are Wild Dog Creek at Apollo Bay, Kennet River, Wye River and the Erskine River at Lorne, which all have lagoons bordered by swamps or low alluvial plains||Not prospective at most river and creek mouths except at Wild Dog Creek, Kennet River, Wye River and Erskine River. Prospective land would only be found downstream of any rocky cascades.|
|Aireys Inlet||Aireys Inlet||The estuary of Painkalac Creek is confined by topography. Painkalac Creek has an extensive tidal flood plain with a freshwater inflow. A Holocene barrier of calcareous sands, blocks the entrance. The barrier may have been in the same position during the mid-Holocene higher sea level but there would have been higher tidal levels behind the barrier. It is apparent from aerial photography that at Old Coach Road, there is an abandoned tidal meander. This suggests that the fluvial sediments have reclaimed down stream land and incised a new non-tidal more sinuous meandering channel. Observations from a site visit indicate that colluvial sediments are moving from east to west and covering previous alluvial and estuarine sediments.||Prospective from Old Coach Road to the outlet and down-slope of the 5 m contour. This is supported by soil sampling. Painkalac Creek has also had periods of poor water quality typical of water affected by actual acid sulfate soil.|
|Angelsea River||Anglesea River is confined by topograpy. It is fringed by swamply tidal flood plains (Coogoorah Park in the north, and in the south, Lions Park and a caravan park). These flood plains are split by a ridge (the Great Ocean Road crosses it). There is a barrier of calcareous sands. |
The estuary and flood plains have been modified. The mouth has been modified by the addition of wall (now buried and sand). The flood plain at Coogoorah Park has been modified during fires in 1983, to control peat fires. Upstream of Coogoorah Park, mining operations have modified the landscape.
|The flood plains south of Coalmine Road are prospective. |
The northern part of this valley floor has been modified and it is difficult to interpret prospectivity from the modern topography. Historical data should be consulted.
Consultant reports and Deakin University research has proved CASS is present. Poor quality, typical of water affected by actual acid sulfate soil was found in Coogoorah Park. The estuary has a history of fish kills and water quality issues typical of water affected by actual acid sulfate soil. However, it is also thought that peat swamps further up the catchment may have disturbed IASS so that this may also contribute to poor water quality events.
|Jan Juc Creek||Jan Juc, Torquay||Jan Juc Creek occupies a narrow valley between a calcarenite cliffed barrier and Jan Juc formation limestone hills. The creek has a narrow flood plain at the foot of the gently inclined slopes of the valley. The plain and foot slopes have been modified during urbanization of the valley. Jan Juc Creek was probably not connected to Spring Creek behind Rocky Point (a cliffed bluff), since exposures along the foot path behind the surf club house reveal clayey soils and the club house is built on a calcarenite cliff.||The narrow flood plain surrounding Jan Juc Creek and its estuary, is prospective. The prospective land is entirely within public reserve and adjacent to the golf course.|
|Spring Creek||Torquay||Spring Creek occupies a narrow defined valley incised into Jan Juc formation limestone before it opens out to the sea. The creek has narrow flood plains and swamps along the estuary. Upstream of the estuary, the creek is confined between higher terraces. Holocene estuarine sediments possibly extend inland in the creek bed, almost to Duffields Road. However, at the upstream end, these sediments would be confined within the modern channel.||The flat land surrounding Spring Creek is prospective from its outlet upstream, beyond Great Ocean Road, to where the valley narrows such that the creek is confined to the modern channel. Prospectivity is limited to about 600 m east of Duffields Road.|
|Thompson Creek||Breamlea, Torquay||Thompson Creek flows laterally to the basalt formed from lava flows from Mount Duneed. Thompson creek has incised into Moorabool sands at the edge of the flow. The flow prevents Thompson Creek from entering the sea further east of Black Rock or joining the Barwon River. |
A barrier has grown westward from Black Rock, to join the Pleistocene barrier (a sand bar across the estuary joins it to Point Impossible) that is welded to the bluff at Torquay.
The basalt also under-lays the shore. It’s shallow depth dissipates the energy of the ocean waves so that the mid-Holocene peak barrier is at the back of the current barrier system and the modern barrier is at the front: the barriers have not migrated far up and down the basalt slope.
There is a depositional basin between the barrier, and the bluff formed on the Moorabool sands west of Thompson Creek and on the basalt on the east. At the back of the mouth of the Thompson Creek estuary (east of the culvert on the Point Impossible Road) there is calcarenite rubble embedded in a mid-Holocene peak platform that is part of a chenier deposit and fore dune.
Tidal influence up the Thompson Creek may be extensive and may go beyond northern extension of Fisher Road but not as far as Horseshoe Bend Road.
Limited sampling to date, does not elucidate what kind of sediments underlay the estuarine sediments or if the estuarine sediments overlay basalt or Moorabool sands.
|Prospective between the bluff and the shoreline. Prospectivity has been proven by 2 sites along Blackgate Road (Rampant et al., 2003; Fitzpatrick et al., 2007). Prospective land extends upstream past the extension of Fisher Road.|
|Barwon River and its lakes swamps and islands including Reedy Lake, Connewarre Lake, Connewarre Swamp, Hospital Swamps, Salt Swamp, Pacey Island and Goat Island||Fyansford, Geelong West, Whittington, Highton, Belmont, Thompson, Leopold, Connewarre, Barwon Heads, Ocean Grove||The Barwon River passes through a series of lakes and swamps before entering the sea at Barwon Heads. The shape of this alluvial/estuarine system is affected by lava flows from the west, the impact of the previous sea rises on what would have been Bellarine Island in the east, by the Moolap plain in the north and the Miocene limestone between Zeally Bay and Salt Swamp, in the south. The Miocene limestone is capped by a series of hardened dune ridges that indicate a complex recent history.|
The lakes and swamps, particularly Reedy Lake, are silting up, burying pre-colonial sediments.
The southern edge of Salt Swamp is marked by a beach ridge (Barwon Heads Road runs along part of it) and a bluff (the eastern end of Bluestone School Road runs along it) which marks the southern Holocene extent of Lake Connewarre.
Murtnagurt Swamp is connected to Lake Connewarre by a drainage line (now modified) which may have been created by a flood-over stream that has incised a broad shallow channel through curved Pleistocene dune ridges. Swales between these dune ridges may have been hydraulically connected to this channel. It is unclear if the Pleistocene dune barrier along Zeally Bay, between Blue Rocks and Point Lonsdale, is and has always been continuous. lies The southern edge of Murtnagurt Swamp is bounded by this barrier.
|Prospectivity land includes the swamps (Salt Swamp, Murtnagurt Swamp, Hospital Swamps), flood plains and islands (Goat Island, Pacey Island) along the Barwon River and extends upstream at least as far as Buckleys Falls. The sediments of the lakes are also prospective. Soil sampling by Fitzpatrick et al. (2007) proved prospectivity in Reedy Lake and Hospital Swamps. The swales between the curved Pleistocene dune ridges (between Bluestone School Road and Barwon Heads) are prospective near the channel connecting Murtnagurt Swamp to Salt Swamp. |
Intensive modification of prospective land and the construction of at least 3 break waters to control tidal salt wedge intrusion, make it difficult to identify the extent of the influence from the tides during the mid-Holocene high sea stand (modern tides are 2 m).
|Point Lonsdale, Victoria Lake and Swan Bay||Ocean Grove Queenscliff, Saint Leonards||A stranded bluff running from Ocean Grove to Saint Leonards, marks the limit of marine submergence. A barrier system extends from Ocean Grove to Point Lonsdale and Shortlands Bluff. It is welded onto the south-western end of the bluff at Ocean Grove. Coastal deposits have been laid in the quieter waters behind this barrier system, and on the lower slopes of the bluff south-west of Saint Leonards. The deposits include a complex series of Holocene features including a shallow bay, i.e. Swan Bay, with tidal flats, that is fronted by barrier islands, e.g. Swan Island, Duck Island, and spits (Edwards Point).|
The barrier system and its hinterland have an impermeable Pleistocene calcarenite base. Calcarenite forms the core of the dunes and stranded beach ridges upon which Holocene features are built. During the Holocene, the sea has entered the swales between the beach ridges and dunes, from the east. There are now swamps and Lake Victoria in these depressions. There are many pits from which shell grit has been extracted. Some are now filled with water.
Yarram Creek and its delta, effectively separates the landscape of stranded barriers from the landscape that fronts the bluff to the west of Swan Bay. The land north of Yarram Creek mainly consists of a shelly beach in front of a low plain in front of the bluff. In some parts alluvial fans extend to the shore. There is little opportunity for cut and fill along this shore, since it is protected by shallow water, easterly aspect, short fetch and barrier islands, as well as the isthmus joining Shortlands Bluff to the mainland, and Shortlands Bluff.
|The low land between the modern barrier and the bluff is prospective. Despite disturbance there are still corridors of prospective land in the barrier system between Yarram Creek and Queenscliff and Ocean Grove. The tidal flats, islands, spits, beach ridges and back swamps surrounding Swan Bay, are prospective. The land surrounding the embayment into which Yarram Creek empties, is also prospective. The alluvial fans deposited along the coast of Swan Bay, are prospective since they may overlay coastal sediments. Prospectivity has been proved by Rampant et al. (2003) and Fitzpatrick et al. (2007).|
|Salt Lagoon||Saint Leonards, Indented Head||A lagoon, possibly a former embayment, formed behind a ridge joining Indented Head and Saint Leonards. The ridge is low and at the southern end, narrow (<40 m). Storm over-wash penetrates the lagoon.||Prospective in the low land.|
|Grassy Point||Portarlington, Indented Head||A former Pleistocene coast with what has been interpreted to be a tidal flat and at least three low beach ridges, now all between the current shoreline and the 5 m AHD contour. A drainage line breaches the former the beach ridges to drain what have may have been former back swamps.||Not prospective. Analysis of LiDAR data suggests that the surface is too high and lacks features that would suggest it has been invaded by the sea during the Holocene.|
|Point Richards||Portarlington, Port Bellarine, Point Richards||A broad cuspate fore land with low gravelly ridges which are Holocene coast lines. The fore land is backed by a bluff. Swamps occupy the land behind and between the ridges. Swamps on private land have been drained.||Prospective between the shore and the bluff. This is supported by soil sampling.|
|Spray Farm Lane||Bellarine||A beach ridge with back swamp that is part of an in-filled embayment into which an ephemeral stream discharges.||Prospective in the low land.|
|Point Henry||Point Henry||Point Henry is cuspate spit composed mainly of shelly sands. It is attached to the coastal bluff on the northern side of a tabular plateau upon which the Alcoa refinery is built. This plateau would have been an island during the last inter-glacial warming of around 120,000 years ago. Most of the surface has been altered, i.e. old geological maps provide information on the geomorphology of this feature.||Prospective in the marshlands behind the beaches composed of shelly sands. Prospectivity of the made land is difficult to interpret, old geological maps should be consulted. Prospectivity has been proven by Fitzpatrick et al. (2007).|
|Port Phillip Bay||Hovells Creek and Limeburners Bay||Hovell Park||A creek that has incised a valley through limestone into basalt during the Pleistocene, which has then been back-filled with estuarine and alluvial sediments during the Holocene. The estuary has a low bluff fringed by Holocene terraces of sand and shells. The upper parts of the estuary are fringed by mangroves and salt marshes.||Prospective in the confined valley downstream of the Princes Freeway, and between the shore of the estuary and the bluff.|
|Point Lillas, Point Wilson and Sand Hummocks||Avalon||Here the low gently sloped surface of the basalt plain is overlain by Holocene beach deposits. A series of shelly beach ridges, salt marshes and lagoons occur between the basalt promontories from Limeburners Bay to Kirk Point. Between Point Lillas and Point Wilson, the land has been extensively modified for a salt works and quarrying.||Prospective between the shore and the inner extent of the Holocene deposits. The extent of prospective land between Point Lillas and Point Wilson is not identifiable due to modifications to the landscape.|